The present invention relates to a method and an apparatus for performing measurements on packagings for a liquid product. Such apparatus have been developed in order to detect the presence of undesired particles such as glass particles in a liquid product. This is important since the presence of such undesired particles can cause damage to the health of end users and can cause financial loss or commercial damage to the suppliers or manufacturers of such liquid products.
The international patent application WO 97/14956 describes a method and apparatus wherein a detection apparatus is described for detecting glass particles in glass bottles filled with beer. The content of this text is deemed interpolated herein by way of reference. In this apparatus beer bottles are rotated about their longitudinal axis, whereafter the beer bottles are stopped abruptly, i.e. decelerated with force. Shortly hereafter the bottle is illuminated with visible light and image recordings are made of the bottle. On the basis of these images a computer determines whether glass particles are present in the bottle.